References Roberts, J. 2002. Does Dark Matter?. UK Dark Matter Collaboration. Department of Physics at Sheffield University. [Available:http://w ww.bbc.co.uk/science/space/deepspace/darkmatter/index.shtml] Kneib, J.-P., Ellis, R. and Treu T. 2003. A Detailed Map of Dark Matter in a Galactic Cluster Reveals How Giant Cosmic Structures Formed. California Institute of Technology. [Available: http://pr.caltech.edu/media/Press_Releases/PR12 414.html] Smith, N. 2003. The UK Dark Matter search at Boulby Mine. UK Dark Matter Collaboration. [Available: http://hepwww.rl.ac.uk/ukdmc/boulby/boulby.html] Rees, M. and Natarajan, P. 2003. A Field Guide to the Invisible Universe. Discover. Vol.24 (12)42-9